1. Field of the Invention
The present invention relates to an information recording device, an information recording method, a recording medium storing an information recording program, an information recording system, an optical-disk recording device, an optical-disk recording method and an optical-disk recording system.
2. Description of the Related Art
An optical-disk recording device that writes data continuously in an optical disk such as a CD-R (CD-Recordable) temporarily stores the data in a buffer prior to the writing thereof to the optical disk. If a data input speed to the buffer is slower than a data write speed to the optical disk for a certain period, the buffer runs out of the data stored therein, and the optical-disk recording device becomes unable to continue writing the data in the optical disk. Such an error is called a buffer under-run error.
An optical-disk recording device disclosed in Japanese Laid-open Patent Application No. 2000-40302 suspends recording data in an optical disk if it decides that the buffer under-run error will occur. On the other hand, if the optical-disk recording device decides that the buffer under-run error has been avoided, it resumes recording the data in the optical disk by starting from a location where the last data item was recorded or where the optical-disk recording device has suspended recording the data.
This optical-disk recording device disclosed in Japanese Laid-open Patent Application No. 2000-40302 can suspend recording data in the optical disk before the buffer under-run error occurs. In addition, this optical-disk recording device can prevent a data recording failure caused by the buffer under-run error, by resuming writing the data in the optical disk only after the data is stored in the buffer for a sufficient amount. Such a method of preventing the data recording failure is called a buffer under-run error preventing function.
The above-described optical-disk recording device carries out phase control to match an expected location of data to be written in the optical disk with an absolute location on the optical disk when the optical-disk recording device starts writing the data in the optical disk. In detail, the optical-disk recording device compares a phase of a synchronous signal “Async” (ATIP Synchronous) with a phase of a synchronous signal “Esync” (Encoder Subcode Synchronous). The synchronous signal “Async” is periodically added to absolute-location information (ATIP) that indicates the absolute location on the optical disk. The synchronous signal “Esync” is periodically added to the data to be written in the optical disk. The optical-disk recording device, then, controls a spinning speed of the optical disk to eliminate a phase error between the signal “Async” and the signal “Esync”.
A resolution of detecting the signal “Async” is comparatively low according to such a phase control, and, thus, some phase error is unavoidable. For example, an instantaneous phase error occurs in the CD-R generally in a range of −2 frames to 2 frames, but is not accumulated. In this case, one frame corresponds to 588 channel bits, and has approximately a 180 μm length. Two frames are approximately 360 μm long.
If the data input speed to the buffer is extremely slow, the above-described optical-disk recording device suspends writing data in the optical disk shortly after starting writing the data in the optical disk, by using the buffer under-run error preventing function. Consequently, the phase error possibly occurs at a suspended location for about −2 to 2 frames with respect to the absolute location on the optical disk.
Additionally, if the optical-disk recording device resumes recording the data in the optical disk from the suspended location, it starts writing the data from a location right after the suspended location to connect the data in sequence. Thus, the phase control possibly starts in a condition in which an initial phase to write the data is shifted by about two frames. Accordingly, if the initial phase is shifted as described above, the optical-disk recording device corrects conditions such as the spinning speed of the optical disk by carrying out the phase control, to eliminate an average phase error of about −2 to 2 frames.
However, if a data recording process is suspended by the buffer under-run error preventing function again while the correction of the conditions is being made by the phase control, the optical-disk recording device normally halts with a remaining phase error. In other words, the instantaneous phase error at the suspended location is shifted about −2 to 2 frames from the average phase error. Thus, the instantaneous phase error may increase by the size of the average phase error.
Accordingly, by repeating the suspension and the resumption of the data recording process, the average phase error is accumulated gradually, and the optical-disk recording device may become unable to correct the phase error at last.
For instance, a sector of a CD is composed of 98 frames. When the phase error becomes larger than one sector, the optical-disk recording device becomes unable to correct the phase error. Consequently, a writing or recording error occurs, or the CD becomes unplayable.